Arrangement for Providing Vehicles with Energy Comprising Magnetizable Material

ABSTRACT

The invention relates to an apparatus for providing vehicles with energy by magnetic induction. The apparatus has a primary side electric conductor and a field shaping layer. The invention also relates to a composite layer for shaping magnetic field lines of an electromagnetic field generated by an electric conductor. The composite layer includes a continuous supporting layer and a plurality of elements made of magnetizable material. Finally, the invention relates to a method of generating an apparatus for providing vehicles with energy by magnetic induction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/400,015, which is the United States national phase of InternationalApplication No. PCT/EP2013/059952 filed May 14, 2013, and claimspriority to United Kingdom Patent Application No. 1208508.0 filed May14, 2012, the disclosures of which are hereby incorporated in theirentirety by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to an arrangement for providing vehicles withenergy by magnetic induction. The arrangement comprises a primary sideelectric conductor arrangement or assembly adapted to generate anelectromagnetic field while an alternating electric current flowsthrough the conductor arrangement and a field shaping layer comprisingmagnetizable material adapted to shape magnetic field lines of theelectromagnetic field.

Furthermore, the invention relates to a corresponding method ofmanufacturing the arrangement and to means adapted to shape magneticfield lines of an electromagnetic field which is produced by theelectric conductor arrangement.

Description of Related Art

During operation of a system for providing vehicles with energy bymagnetic induction, the electromagnetic field which is generated by theprimary side electric conductor arrangement is received by a receivingdevice on the secondary side (the side of the vehicle) and theelectromagnetic field energy is converted back into electric energy bymagnetic induction. The invention especially relates to the primary sideof such a system. The receiving device can be named “pick-up” and ispart of the vehicle, while the primary side electric conductorarrangement is typically buried in the ground or is otherwisemechanically connected to the track of the vehicle or to the place wherethe vehicle may stop or may be parked.

The terms “primary side” and “secondary side” are used corresponding tothe terminology which is used for transformers. In fact, the electricparts of a system for transferring electric energy from a vehicle trackor from a vehicle stop to the vehicle by induction form a kind oftransformer. The only difference compared to a conventional transformeris the fact that the vehicle, and thus the secondary side, can move.

WO 2010/000495 A1 describes a system and method for transferringelectric energy to a vehicle. The energy can be transferred to thevehicle while the vehicle is moving. While the present invention mayrelate to such a system, it is not restricted to the transfer of energyto moving vehicles. Rather, the energy may be transferred while thevehicle temporarily stops (such as a bus at a bus stop) or while thevehicle is parked.

The vehicle may be any land vehicle, including track bound vehicles,such as conventional rail vehicles, mono-rail vehicles, trolley bussesand vehicles which are guided on a track by other means. Other examplesof land vehicles are road automobiles, including busses which are nottrack bound. For example, the vehicle may be a vehicle having anelectrically operated propulsion motor. The vehicle may also be avehicle having a hybrid propulsion system, e.g. a system which can beoperated by electric energy or by other energy, such aselectrochemically stored energy or fuel (e.g. natural gas, gasoline orpetrol).

WO 2010/000495 A1 describes an example of serpentine windings on theprimary side for producing the electromagnetic field. The primary sideconductor assembly of the present invention, which is made ofelectrically conducting material that produces the electromagnetic fieldduring operation while the electrically conducting material carries analternating electric current, may have the same or a differentconfiguration. In any case, at least sections and/or parts of theprimary side conductor assembly has/have a length and a width, so thatthe primary side conductor assembly comprises lateral edges. Forexample, as described in WO 2010/000495 A1, sections of the primary sideconductor assembly may extend along the track of the vehicle so thatthere are two lateral edges on opposite sides of the primary sideconductor assembly. Other configurations are possible such as elongatedelectric conductors extending in the direction of travel, coils ofelectric conductors having several windings and arrangements of electricconductors having different configurations.

The features of a primary side conductor assembly which are described inthe foregoing description may also apply to a secondary side conductorassembly, with the exception that this assembly is located on board thevehicle.

In any case, the primary side conductor assembly causes emissions of theelectromagnetic field, which is produced by the primary side conductorassembly, to the surroundings. Corresponding limit values, in particularof the electromagnetic or magnetic field strength, must be observed. Inaddition, the secondary side conductor assembly also causes emissions.

The primary side conductor assembly and the secondary side conductorassembly should be coupled to each other in an effective manner.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide anarrangement for providing vehicles with energy by magnetic induction, toprovide a corresponding method of manufacturing such an arrangement andto provide suitable means so that the energy can be transferred from theprimary side to the secondary side in an effective manner and so thatthe field strength in at least a part of the surroundings is reduced.

It is a basic idea of the present invention to use magnetizable materialin order to shield a part of the surroundings, in particular the areabelow the primary side conductor arrangement, from the electromagneticfield(s) produced by the primary side conductor assembly. Therefore, ashielding assembly comprising magnetizable material is combined with theconductor assembly. Preferably, the shielding assembly may also compriseelectrically conducting material which is, in particular, notmagnetizable material. An example is aluminum. In particular, theelectric conductivity of the electrically conducting material is higherthan the electric conductivity of the magnetizable material by a factorof at least 1,000 (thousand), preferably by a factor of at least 10,000(ten thousand). For example, in practice, the electric conductivity offerrite may be in the range of 10⁻⁷ to 1 A/(Vm) and the electricconductivity of the electrically conducting material (for example ametal, such as aluminum) may be in the range of 10⁶ to 10⁸ A/(Vm).

In particular, the shielding assembly or a part of the shieldingassembly may extend below the primary side conductor assembly, below thelevel of the conductor assembly. As a result, regions which are locatedbeyond the magnetizable material (if viewed from the conductor assembly)are shielded from the electromagnetic field produced by the conductorassembly.

If there is also electrically conducting material, a system fortransferring electric energy to a vehicle, in particular to a roadautomobile or to a track bound vehicle such as a light rail vehicle, maycomprise the primary side electric conductor arrangement for producing amagnetic field and for thereby transferring the energy to the secondaryside, wherein the current line or lines of the primary side electricconductor arrangement extend(s) at a first height level, an electricallyconductive shield for shielding the magnetic field extends below thefirst height level, and the magnetizable material extends at a secondheight level above the shield. This arrangement can, in addition oralternatively, be used sideways of the primary side electric conductorarrangement, i.e. the electrically conductive material is placed beyondthe magnetizable material, if viewed from the current line or lines ofthe conductor arrangement. This arrangement can be modified by replacingthe layer of magnetizable material consisting of magnetizable materialelements by a continuous layer made of magnetizable material.

In particular, magnetizable material can be used which has smallelectric conductibility, for example ferrites. As a result, the effectsof electric currents which are induced in the shielding material arereduced. More generally speaking, the magnetizable material may beferromagnetic, paramagnetic or ferrimagnetic. It is preferred that themagnetizable material has a magnetic susceptibility of at least 10,preferably at least 50.

Using magnetizable material as shielding material has the advantage thatflux lines of the magnetic field are guided within the material.Therefore, the material can be characterized as magnetic field line(i.e. magnetic flux line) shaping material. Compared to the situationwithout the presence of the shielding material, at least some of themagnetic flux lines cannot permeate the magnetizable material. Instead,these magnetic flux lines are redirected in the direction of extensionof the magnetizable material.

Furthermore, the magnetizable material has the effect that it canconcentrate or bundle the magnetic flux lines of the field in the areabetween the primary side conductor assembly and the secondary sidereceiving device. However, the relative position of the receiving deviceand the primary side conductor arrangement can vary, since the vehiclemay drive or may stop at different positions. Since the density of themagnetic flux lines (i.e. the field strength) also varies, especially ifviewed in the direction of the lateral horizontal direction of a vehicletrack, the degree of efficiency of the transfer of power from theprimary side to the secondary side also varies with the relevantposition of the receiving device and the primary side conductorassembly. However, it is desired that the impact of this dependency isreduced.

It is therefore proposed to use a field shaping layer comprisingmagnetizable material. In particular, the field shaping layer ispositioned beyond the primary side conductor arrangement, if viewed fromthe receiving device (in particular if viewed from above). If the trackor vehicle stop extends horizontally, the field shaping layer isintegrated preferably in a construction under the primary side conductorarrangement. In particular, this construction may be the construction ofa railway or of a road for automobiles. Alternatively, the constructionmay be the construction of a parking area for parking at least onevehicle.

In order to reduce the dependency of the power transfer efficiency onthe relative position of the receiving device and the primary sideconductor assembly, it is proposed that the field shaping layercomprises a plurality of elements made of the magnetizable material,wherein neighbouring elements are positioned at a distance to eachother.

In particular, the following is proposed:

An arrangement for providing vehicles with energy by magnetic induction,wherein the arrangement comprises:

-   -   a primary side electric conductor arrangement adapted to        generate an electromagnetic field while an alternating electric        current flows through the conductor arrangement and    -   a field shaping layer comprising magnetizable material adapted        to shape magnetic field lines of the electromagnetic field,        wherein the field shaping layer comprises a plurality of        elements made of the magnetizable material, wherein neighbouring        elements are positioned at a distance to each other.

Furthermore, a method is proposed of generating an arrangement forproviding vehicles with energy by magnetic induction, wherein:

-   -   a primary side electric conductor arrangement, adapted to        generate an electromagnetic field while an alternating electric        current flows through the conductor arrangement, is provided and    -   a field shaping layer, comprising magnetizable material adapted        to shape magnetic field lines of the electromagnetic field, is        arranged in the ambience of the conductor arrangement,        wherein the field shaping layer is arranged using a plurality of        elements made of the magnetizable material, wherein neighbouring        elements are positioned at a distance to each other.

In particular, the elements may be in the shape of tiles. The tiles maytherefore comprise parallel (in particular planar) upper and lowersurfaces. Therefore, a vertical cross section through the tile maycomprise a rectangular shaped outline of the tile, wherein the upper andlower surfaces form the parallel upper and lower straight linearsections of the outline. Preferably, all elements or at least themajority of the elements of the field shaping layer may have the sameshape. In addition, it is preferred that the elements of the fieldshaping layer are positioned in the same plane. If the layer extends ina horizontal plane, the upper surfaces of tile-shaped elements of thelayer are positioned in a common horizontal plane and the same appliesto the lower surfaces. However, it is an advantage of the field shapinglayer comprising a plurality of elements positioned at a distance toeach other that there is some flexibility with respect to thepositioning of the elements. For example, if the surface of the base, onwhich the field shaping layer is to be positioned, is not exactly smoothor planar, the extension of the field shaping layer will also benon-planar. It is a further advantage of the proposed configuration ofthe field shaping layer that deviations of the elements from an idealposition within a plane modify the magnetic flux density beyond theprimary side conductor arrangement only slightly.

A further advantage of the field shaping layer according to the presentinvention is the fact that the resulting inductance of the system, whichincludes the primary side conductor assembly and the secondary sidereceiving device, is not sensitive to the relative position of thereceiving device and the primary side conductor assembly. This appliesto vertical and lateral displacement of the receiving device. Therefore,if the receiving device is adapted to be operated in resonance, changesto the relative position will not significantly reduce the efficiency ofpower transfer. The total arrangement which is adapted to transferenergy from the primary side to the secondary side may comprise acontrol for controlling the electric properties of the primary sideand/or secondary side so that the receiving device is operated inresonance. However, at least in some applications, such a control is nolonger necessary, since the arrangement is not sensitive to changes inthe relative position.

In particular, the distance between two neighbouring elements is smallerthan the extension of the neighbouring elements in the direction acrossthe distance. Preferably, the distance is smaller by at least a factorof five and preferably by a factor of ten (i.e. the distance multipliedby the factor is equal to the extension).

In particular, the outline of the individual elements of the layer inthe direction perpendicular to the layer may have any shape. It ispreferred that the outline is shaped in such a manner that the distancesto each of the neighbouring elements can have the same size. A preferredoutline shape is rectangular or quadratic. However, it would also bepossible to use elements having a regular hexagonal outline (e.g. anarrangement of the elements like a honeycomb structure), a circularoutline, an oval outline or a triangular outline, for example.

In view of the manufacture of the arrangement, i.e. in view of theprocess of placing the elements of the layer on site, it is preferredthat gaps between pairs of neighbouring elements are aligned with gapsof other pairs of neighbouring elements so that there is at least onecontinuous straight gap extending in a longitudinal direction and/orthat there is at least one continuous straight gap between differentpairs extending in a lateral direction, perpendicular to thelongitudinal direction of the layer. Therefore, it is preferred that theoutline of the elements is rectangular or quadratic and that theelements of the layer all have the same size, so that the elements canbe arranged in columns and rows, if viewed in a direction perpendicularto the layer. The straight gaps also follow the lines of the columns androws, in this case.

If there is at least one straight continuous gap extending from one sideof the layer to the opposite side, and if the elements are fixed on aflexible support material, the layer can be pre-fabricated by fixing theelements on the flexible support material and folding the layer alongthe straight continuous gap. If there are several straight continuousgaps, the pre-fabricated arrangement can be folded multiply. Forexample, if there is a multiplicity of straight continuous gaps whichextend parallel to each other, the pre-fabricated arrangement can befolded along these parallel straight gaps and the required space duringtransport of the pre-fabricated arrangement to the location on site,where the arrangement is to be operated, is significantly reduced. Forexample, the pre-fabricated arrangement can be folded in the manner of acoil or in the form of serpentines.

In the following, a composite layer is described as a means for shapingmagnetic field lines of an electromagnetic field generated by anelectric conductor arrangement. The continuous supporting layer of thiscomposite layer may be the flexible material mentioned above. Thecomposite layer comprises a plurality of the elements made ofmagnetizable material (preferably a ferrite), wherein the elements arepositioned at a distance to each other and are fixed on the supportinglayer. Again, the elements can be in the shape of tiles, for example thetiles mentioned above.

Preferably, the elements are evenly distributed over the extension ofthe field shaping layer in a longitudinal direction of the layer and/orin a lateral direction of the layer.

According to a preferred embodiment, the continuous supporting layer(e.g. a sheet of metal) is made of an electrically conducting material.For example, the electrically conducting material may be aluminum, whichmay be annealed aluminum, so that it is flexible and can be folded atleast at one straight gap.

Preferably, the continuous supporting layer made of the electricallyconducting material is positioned further away from the primary sideconductor arrangement than the elements made of magnetizable material.

The additional layer of electrically conducting material (the sameapplies to an alternative embodiment where the layer of electricallyconducting material is not a layer to which the magnetizable elementsare fixed) has the advantage that it provides an additional shieldingeffect. The area beyond the electrically conducting material iseffectively shielded from electromagnetic fields, in particular fieldsproduced by the primary side conductor arrangement.

In particular, if the elements are in the shape of tiles and if there isa distance or gap in between each pair of neighbouring elements, thearrangement can be called a mosaic. The tiles are preferably evenly(i.e. in a homogeneous manner) distributed over the extension of thelayer.

For example, the individual elements can be manufactured by casting.Preferably, the magnetizable material is a ferrite material in thiscase.

In particular, the elements of magnetizable material can be fixed to thesupporting layer, in particular to the supporting layer made ofelectrically conducting material, using an additional connectingmaterial, which is preferably also flexible (like the preferredembodiment of the supporting material). The connecting material may bean adhesive, such as a polymer or any other plastic material.Consequently, the elements of magnetizable material are positioned at adistance to the supporting material. In case of a metal material assupporting material, the shielding effect is improved and corrosion canbe excluded. The distance between the elements (for example ferriteelements) and the metal supporting layer (for example made of aluminum)is preferably in the range of some millimetres.

In particular, a composite layer comprising the continuous supportinglayer and the elements, the composite layer being wound in the form of acoil or being folded in sections on top of each other, can be providedto and placed at a part of an target area on site and can be unwound orunfolded so that it occupies the target area.

Especially in the case of the composite layer, but also in otherembodiments of the arrangement, the magnetizable material is preferablycombined with electrically conducting material (as mentioned above). Ifviewed from the primary side electric conductor arrangement, there is alayer comprising the elements of the magnetizable material (in short:the magnetic layer), wherein the neighbouring elements are positioned ata distance to each other, thereby leaving gaps in between the elements.Furthermore, still viewed from the primary side electric conductorarrangement, the electrically conducting material is located beyond themagnetic layer, wherein the electrically conducting material is at leastpositioned behind the gaps in between the elements and preferably formsa continuous layer behind the magnetic layer. In any case, electricallyconducting material may also be located behind areas (i.e. behind amargin) outside of the outline of the arrangement of the elements, forexample if the continuous layer extends beyond the outline of thearrangement of the elements. Thereby, the electrically conductingmaterial covers at least the gaps, wherein the electrically conductingmaterial optionally comprises through holes so that only a part of thearea of the gaps or margin is covered.

Consequently, hypothetical rays extending from the primary side electricconductor arrangement towards the magnetic layer in straight directionsperpendicular to the magnetic layer either impinge on one of theelements of magnetizable material or pass a gap (or more generallyspeaking: impinge on a region free of magnetizable material). The raysimpinging on a region free of magnetizable material pass the region andimpinge on the electrically conducting material or—optionally—pass athrough hole of the electrically conducting material. Of course, inpractice, these hypothetical rays would penetrate any other material ofthe arrangement in between the primary side electric conductorarrangement and the magnetic layer and optionally would also penetrateany material (which is neither magnetisable material nor electricallyconducting material) in the gaps and/or between the magnetic layer andthe electrically conducting material. As a result, the area within themagnetic layer which is occupied by the elements of magnetizablematerial (which is the sum of the areas defined by the outlines of theindividual elements) can be calculated as the total magnetic area viewedby the primary side electric conductor arrangement. Furthermore, thearea behind the magnetic layer which is occupied by the electricallyconducting material can be calculated as the total electricallyconducting area viewed by the primary side electric conductorarrangement. If there are no through holes in the electricallyconducting material, the area of the gaps within the magnetic layer(plus the area of any margin, see above) is equal to the totalelectrically conducting area.

According to the preferred embodiment, the ratio of the total magneticarea to the total area of the magnetic layer (i.e. the sum of the totalmagnetic area and the area of the regions free of magnetizable material)is at least 70%, preferably at least 81% and most preferred at least84%. Still according to the preferred embodiment, the ratio of the totalmagnetic area to the total area of the magnetic layer is not greaterthan 97%, preferably not greater than 94% and most preferred not greaterthan 89%.

This ratio of the total magnetic area to the total area of the magneticlayer has the advantage that the (above-mentioned) sensitivity of theresulting inductance of the system for transferring energy from theprimary side conductor assembly to the secondary side receiving devicewith respect to the relative position of the receiving device and theprimary side conductor assembly is particularly small. In particular,the ratio depends on the distance of the primary side conductor assemblyto the magnetic layer. Preferably, this distance is not greater than 20cm. In this case, the ratio can be chosen so that it is at least 81% andpreferably at least 84% and can be chosen so that it is not greater than94% and preferably not greater than 89%. In particular, if these valueslimits are met, the inductance of a coil of an electric conductor (seebelow) does not vary by more than plus or minus 5% if the coil'sdistance to the magnetic layer is varied from 30 cm by plus or minus 10cm.

More generally speaking, the ratio of the area within the field shapinglayer (mentioned above) occupied by the elements made of magnetizablematerial on one hand to the total area of the field shaping layer,including regions within the field shaping layer free of magnetizablematerial, on the other hand is preferably within these limits. Withrespect to the composite layer mentioned above, the plurality ofelements made of magnetizable material are preferably arranged so as toform a magnetic layer, wherein the ratio of the area within the magneticlayer occupied by the elements made of magnetizable material on one handto the total area of the magnetic layer, including regions within themagnetic layer free of magnetizable material, on the other hand ispreferably within these limits.

The combination of the magnetizable material leaving gaps in between theelements which are covered on the back side by electrically conductingmaterial has a compensating effect on the inductance of a coil of anelectric conductor: the closer the coil is located to electricallyconducting material, the smaller the inductance, and the closer the coilis located to magnetizable material, the greater the inductance. Thecompensating effect of the combination of the materials is the reasonfor the reduced sensitivity with respect to the relative position of thereceiving device and the primary side conductor assembly.

In particular, the invention can be applied to the construction of aroute (such as a railway or a road) for vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples and preferred embodiments of the invention will be describedwith reference to the attached figures which show:

FIG. 1 a schematic top view of a composite layer comprising a pluralityof elements made of magnetizable material which are arranged in rows andcolumns on a supporting layer,

FIG. 2 a schematic top view similar to the arrangement shown in FIG. 1,wherein the elements are rectangular elements extending from one side ofthe arrangement to the opposite side,

FIG. 3 an enlarged view of the area of the arrangement shown in FIG. 1which is marked by dashed line III,

FIG. 4 a schematic representation of a cross-section of an arrangementincluding the surface of a track or road on which a vehicle may travelor may stop, an embedded primary side conductor arrangement and acomposite layer similar to the layer shown in FIG. 1, and

FIG. 5 the composite layer of FIG. 4, wherein the layer is foldedslightly along three straight gaps between elements.

DESCRIPTION OF THE INVENTION

The arrangement shown in FIG. 1 comprises in total sixty elements madeof magnetizable material, some of the elements are denoted by 1. Theelements 1 are arranged in columns of in each case five elements 1 androws of in each case twelve elements 1. The number of elements percolumn and row is just an example, may vary and depends in practice onthe desired configuration, in particular on the desired dimensions ofthe layer.

There is a distance between each pair of neighboring elements 1 (seealso FIG. 3) so that corresponding gaps 2 exist between the neighboringelements 1, which gaps are free of magnetizable material. In practice,these gaps may be free of material at all or may at least partly containother (non-magnetizable) material.

There is a supporting layer 3 under the elements 1. As also shown inFIG. 3, the outline of the supporting layer 3 extends at a distance 22to the edges of the elements 1 a, 1 b, 1 c which are positioned next tothe outline of the supporting layer 3.

The gaps in between two neighboring elements 1, for example betweenelement 1 a and element 1 c, are denoted by reference numeral 2 and theletter which is used to denote the neighboring elements (for example,the gap in between the neighboring elements 1 a, 1 c is denoted by 2 a,2 c in FIG. 3). The gaps are aligned to form straight continuous gaps.In particular, the gaps between all pairs of neighboring elements 1 havethe same widths (i.e. the distance between the neighboring elements isthe same).

For example, in case of the embodiment shown in FIG. 1, the lengths (inhorizontal direction of FIG. 1) and widths (in vertical direction ofFIG. 1) of the elements 1 may be equal and may amount to 10 cm. In thiscase, the distance between any two neighboring elements 1 across thecorresponding gap 2 may be in the range of 0.75 to 1.25 cm, preferablyin the range of 0.9 to 1.1 cm and may amount to 1 cm, for example.

As will be described in connection with FIG. 5, the supporting layer canbe folded along the continuous straight gaps. This is also possible withthe modified arrangements shown in FIG. 2, although this kind ofcomposite layer is not preferred. The elements 11 of the arrangementshown in FIG. 2 are wider in lateral direction (the vertical directionin FIG. 2) compared to the arrangement shown in FIG. 1. The individualelements 11 extend from one side in lateral direction to the oppositeside in lateral direction. The supporting layer under the elements 11 isdenoted by 13.

For example, in case of the embodiment shown in FIG. 2, the lengths (inhorizontal direction of FIG. 1) of the elements 11 may be equal and mayamount to 10 cm. In this case, the distance between any two neighboringelements 11 across the corresponding gaps may be in the range of 0.85 to1.35 cm, preferably in the range of 1.0 to 1.2 cm and may amount to 1.1cm, for example.

Other than shown in FIGS. 1 and 2, the distance there may be no distancebetween the outline of the supporting layer 3; 13 to the edges of theelements 1; 11, if viewed from above.

The cross-section shown in FIG. 4 can be interpreted in a differentmanner. In one case, the horizontal direction of FIG. 4 extends inlongitudinal direction, so that the direction perpendicular to the imageplane of FIG. 4 is the lateral direction. In this case, the number ofelements 1 e, 1 f, 1 g, 1 h is preferably not the total number ofconsecutive elements made of magnetizable material which are arranged inlongitudinal direction one behind the other.

According to another interpretation of FIG. 4, the horizontal directionof the figure is the lateral direction so that the longitudinaldirection of the field shaping layer extends perpendicular to the imageplane of FIG. 4. In this case, the number of four elements 1 e, 1 f, 1g, 1 h which are positioned next to each other in a consecutive mannermay be the total number of elements (but there may be more consecutiveelements in lateral direction or fewer elements, in practice). In anycase, the elements 1 are supported by a supporting layer 23. Inparticular, the elements 1 may be fixed on the upper surface of thesupporting layer 23, for example using an adhesive. The adhesive is notshown and due to the presence of the adhesive, the elements 1 may bepositioned at a distance (e.g. of some mm) in vertical direction, i.e.above the upper surface of the supporting layer.

At a distance above the upper surfaces of the elements 1, a primary sideconductor arrangement 26 is located which produces—during operation—theelectromagnetic field which is to be received by a receiving device of avehicle (not shown). In the example of FIG. 4, the primary sideconductor arrangement 26 is buried in the ground or integrated in thetrack of the vehicle and the surface of the track is denoted by 25.

The course of some magnetic flux lines F is shown in FIG. 4. However,only sections of the flux lines F in the area of the elements 1 areshown. The flux lines F are curved along their extension from above theelements 1, since the magnetizable material of the elements 1 redirectthe flux lines F so as to follow the extension of the magnetizablematerial. The flux lines F shown are just examples. Other flux lines mayenter the material of the elements 1 at other locations, for example atthe upper surface of an element 1.

The horizontal extension of the field shaping layer according to theillustrations of FIG. 1-FIG. 4 is preferred, but not the only way ofusing a field shaping layer in connection with a primary side conductorarrangement. For example, the field shaping layer or an additional fieldshaping layer may be inclined with respect to the horizontal planeand/or may be positioned in lateral direction of the primary sideconductor arrangement. It is also possible, that the same compositelayer comprising a supporting layer and elements fixed to the supportinglayer extends under and sideways (in lateral direction) of a primaryside conductor arrangement.

FIG. 5 shows that for example the composite layer 23, 1 e-1 h of FIG. 4can be folded along the gaps between the neighboring elements 1. In thestate shown in FIG. 5, the composite layer is folded along each of thethree gaps 2 ef, 2 fg, 2 gh. The folding angle shown in FIG. 5 is 20degrees, but depending on the flexibility of the supporting layer 23 anddepending on the width of the respective gap in between neighboringelements 1, the folding angle can be larger. For example, thearrangement shown in FIG. 5 can be folded to form a coil or to formlayer sections which are stacked upon each other.

The invention claimed is:
 1. An apparatus for providing vehicles withenergy by magnetic induction, wherein the apparatus comprises: a primaryside electric conductor configured to generate an electromagnetic fieldwhile an alternating electric current flows through the conductor and afield shaping layer comprising magnetizable material configured to shapemagnetic field lines of the electromagnetic field, wherein the fieldshaping layer comprises a plurality of elements made of the magnetizablematerial fixed to a continuous supporting layer made of electricallyconducting material that is non-magnetic, wherein neighboring elementsare positioned at a distance to each other and wherein the continuoussupporting layer is arranged—if viewed from the primary side electricconductor—behind the field shaping layer, wherein the plurality ofelements made of the magnetizable material is arranged in rows andcolumns with gaps in between each pair of neighboring elements in therows and in the columns, so that the plurality of elements made of themagnetizable material occupies a magnetizable fraction of a total areaof the field shaping layer which magnetizable fraction does not includethe gaps, so that only an area of the continuous supporting layer equalto a size of the magnetizable fraction of the total area of the fieldshaping layer is covered by the plurality of elements made of themagnetizable material and so that a remaining part of a total area ofthe continuous supporting layer is not covered by the plurality ofelements made of the magnetizable material; wherein the size of themagnetizable fraction of the total area of the field shaping layer isnot greater than 89 percent and not smaller than 81 percent of the totalarea of the continuous supporting layer.
 2. The apparatus of claim 1,wherein the distance between two neighboring elements is smaller than anextension of the neighboring elements in a direction across thedistance.
 3. The apparatus of claim 1, wherein a ratio of an area withinthe field shaping layer occupied by the elements made of magnetizablematerial on one hand to a total area of the field shaping layer,including regions within the field shaping layer free of magnetizablematerial, on the other hand is at least 70% and is not greater than 97%.4. The apparatus of claim 1, wherein the elements are in the shape oftiles.
 5. The apparatus of claim 1, wherein the elements are evenlydistributed over an extension of the field shaping layer in alongitudinal direction of the layer or in a lateral direction of thelayer.
 6. A composite layer for shaping magnetic field lines of anelectromagnetic field generated by an electric conductor, wherein thecomposite layer comprises: a continuous supporting layer made ofelectrically conducting material that is non-magnetic and a fieldshaping layer comprising a plurality of elements made of magnetizablematerial, wherein the elements are positioned at a distance to eachother and are fixed to the continuous supporting layer, whereinneighboring elements are positioned at a distance to each other; whereinthe plurality of elements made of the magnetizable material is arrangedin rows and columns with gaps in between each pair of neighboringelements in the rows and in the columns, so that the plurality ofelements made of the magnetizable material occupies a magnetizablefraction of a total area of the field shaping layer which magnetizablefraction does not include the gaps, so that only an area of thecontinuous supporting layer equal to a size of the magnetizable fractionof the total area of the field shaping layer is covered by the pluralityof elements made of the magnetizable material and so that a remainingpart of a total area of the continuous supporting layer is not coveredby the plurality of elements made of the magnetizable material; whereinthe size of the magnetizable fraction of the total area of the fieldshaping layer is not greater than 89 percent and not smaller than 81percent of the total area of the continuous supporting layer.
 7. Thecomposite layer of claim 6, wherein the plurality of elements made ofmagnetizable material are arranged so as to form a magnetic layer andwherein a ratio of an area within the magnetic layer occupied by theelements made of magnetizable material on one hand to a total area ofthe magnetic layer, including regions within the magnetic layer free ofmagnetizable material, on the other hand is at least 70% and is notgreater than 97%.
 8. The composite layer of claim 6, wherein theelements are in the shape of tiles.
 9. The composite layer of claim 6,wherein the elements are evenly distributed over an extension of a fieldshaping layer in a longitudinal direction of the layer or in a lateraldirection of the layer.
 10. The composite layer of claim 6, wherein thecontinuous supporting layer is made of an electrically conductingmaterial.
 11. A method of generating an apparatus for providing vehicleswith energy by magnetic induction, wherein: a primary side electricconductor, adapted to generate an electromagnetic field while analternating electric current flows through the conductor arrangement, isprovided and a field shaping layer, comprising a plurality of elementsmade of magnetizable material adapted to shape magnetic field lines ofthe electromagnetic field, is arranged in an ambience of the conductorarrangement, wherein neighboring elements of the plurality of elementsare positioned at a distance to each other; wherein the plurality ofelements made of the magnetizable material is arranged in rows andcolumns with gaps in between each pair of neighboring elements in therows and in the columns, so that the plurality of elements made of themagnetizable material occupies a magnetizable fraction of a total areaof the field shaping layer which magnetizable fraction does not includethe gaps, so that only an area of the continuous supporting layer equalto a size of the magnetizable fraction of the total area of the fieldshaping layer is covered by the plurality of elements made of themagnetizable material and so that a remaining part of a total area ofthe continuous supporting layer is not covered by the plurality ofelements made of the magnetizable material; wherein the size of themagnetizable fraction of the total area of the field shaping layer isnot greater than 89 percent and not smaller than 81 percent of the totalarea of the continuous supporting layer.
 12. The method of claim 11,wherein a ratio of an area within the field shaping layer occupied bythe elements made of magnetizable material on one hand to a total areaof the field shaping layer, including regions within the field shapinglayer free of magnetizable material, is at least 70% and is not greaterthan 97%.
 13. The method of claim 11, wherein the field shaping layer isconstituted as a composite layer.
 14. The method of claim 11, whereinneighboring elements are positioned at a distance to each other which issmaller than an extension of the neighboring elements in a directionacross the distance.
 15. The method of claim 11, wherein the elementsare evenly distributed over an extension of the field shaping layer in alongitudinal direction of the layer or in a lateral direction of thelayer.
 16. The method of claim 11, wherein a composite layer comprisingthe continuous supporting layer and the elements, the composite layerbeing wound in the form of a coil or being folded in sections on top ofeach other, is provided to and placed at a part of a target area on siteand is unwound or unfolded so that it occupies the target area.